planting under mulch

I put in 2" of compost mulch this year. When I go to plant small bulbs which normally go 2-3" deep in the ground, is that 2" + 2-3"? Won't they have trouble coming up 5"? Things like scilla or squill are only 4" high once they appear.

I have never had mulch keep anything from growing, including weeds. I have only used organic mulch, nothing like ground tires.

Same here!

If I were planting in my garden, I would only be placing the bulbs 2-3" below the current surface. Your compost mulch will soon be turning into soil anyway so you should be good to go.